bugs fixed, improvement of loading

Author: katcom

app/src/main/java/com/katcom/androidFileVault/FileManager.java

@@ -4,6 +4,7 @@
 import android.content.Intent;
 import android.graphics.Bitmap;
 import android.net.Uri;
+import android.os.AsyncTask;
 import android.os.Bundle;
 import androidx.fragment.app.Fragment;
 import androidx.appcompat.app.AlertDialog;
@@ -16,12 +17,18 @@
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ImageView;
+import android.widget.ProgressBar;
 import android.widget.Toolbar;
 
+import java.io.File;
 import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
 import java.security.UnrecoverableEntryException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
 
 public class ImageViewerFragment extends Fragment {
     private static final String ARG_FILE = "file";
@@ -30,7 +37,9 @@ public class ImageViewerFragment extends Fragment {
     private ImageView mImageView;
     private ProtectedFile mFile;
     private int WRITE_REQUEST_CODE = 0;
-
+    private Bitmap picture;
+    private ProgressBar mProgressBar;
+    private Executor executor;
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         View view = inflater.inflate(R.layout.fragment_image_viewer, container, false);
@@ -42,9 +51,14 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle sa
         String imgName = mFile.getFilename();
 
         mImageView = view.findViewById(R.id.fragment_image_viwer_image_view); // Bind the controller to the image view in the layout
+        mImageView.setVisibility(View.GONE);   // hide the image until it is loaded
 
-        mImageView.setImageBitmap(FileManager.get(getContext()).getPreview(mFile,700,700));
+        mProgressBar = view.findViewById(R.id.image_viewer_progressBar);
+        mProgressBar.setVisibility(View.VISIBLE); // Show the progress bar while loading
 
+        //mImageView.setImageBitmap(FileManager.get(getContext()).getPreview(mFile,700,700));
+        executor = Executors.newFixedThreadPool(2);
+        new LoadingImageTask().executeOnExecutor(executor,mFile);
         getActivity().setTitle(imgName);
         return view;
     }
@@ -99,9 +113,31 @@ private void export(Uri uri) {
         FileManager vault = FileManager.get(getContext());
         try {
             vault.exportFile(mFile,getContext().getContentResolver().openOutputStream(uri));
-        } catch (FileNotFoundException | NoSuchAlgorithmException | KeyStoreException | UnrecoverableEntryException e) {
+        } catch (NoSuchAlgorithmException | KeyStoreException | UnrecoverableEntryException  | IOException e) {
             Log.e(TAG,e.toString());
         }
 
     }
+
+    private class LoadingImageTask extends AsyncTask<ProtectedFile,Void,Void> {
+        File file;
+        InputStream in;
+
+        @Override
+        protected Void doInBackground(ProtectedFile... files) {
+            picture = new PreviewManager(getContext()).getPreview(mFile,700,700);
+            return null;
+        }
+
+        @Override
+        protected void onPostExecute(Void aVoid) {
+            updateUI();
+        }
+    }
+
+    private void updateUI() {
+        mProgressBar.setVisibility(View.GONE);
+        mImageView.setVisibility(View.VISIBLE);
+        mImageView.setImageBitmap(picture);
+    }
 }

app/src/main/java/com/katcom/androidFileVault/ImageViewerFragment.java

@@ -0,0 +1,66 @@
+package com.katcom.androidFileVault;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.KeyStoreException;
+import java.security.NoSuchAlgorithmException;
+import java.security.UnrecoverableEntryException;
+
+public class PreviewManager {
+    private Context mContext;
+    private final static String TAG = "Preview Manager";
+    public PreviewManager(Context context) {
+        mContext =context;
+    }
+
+    /**
+     * This method returns a scaled thumbnail of a picture in form of a Bitmap,
+     * given the size of the container of the thumbnail picture.
+     * We need to make it run on the back ground for fast loading speed
+     * @param file
+     * @param sizeX
+     * @param sizeY
+     * @return
+     */
+    public Bitmap getPreview(ProtectedFile file,int sizeX,int sizeY){
+            Bitmap bitmap;
+            try {
+                FileManager vault = FileManager.get(mContext);
+
+                InputStream in = vault.getDecryptedInputStream(file.getFilepath());
+                //ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
+                BitmapFactory.Options options = new BitmapFactory.Options();
+                options.inJustDecodeBounds = true;
+                BitmapFactory.decodeStream(in,null,options);
+
+                float srcWidth = options.outWidth;
+                float srcHeight = options.outHeight;
+                String message = "Width : " + srcWidth + " Height : " + srcHeight;
+                Log.i(TAG,message);
+
+                int inSampleSize = Utils.calculateInSampleSize(options,sizeX,sizeY);
+
+                options = new BitmapFactory.Options();
+                options.inSampleSize = inSampleSize;
+                in = vault.getDecryptedInputStream(file);
+                //in.close();
+                return BitmapFactory.decodeStream(in,null,options);
+            } catch (UnrecoverableEntryException | NoSuchAlgorithmException | KeyStoreException | IOException e) {
+                Log.e(TAG,e.toString());
+            }
+
+            bitmap = getDefaultPreview();
+            return bitmap;
+        }
+
+    private Bitmap getDefaultPreview() {
+        return BitmapFactory.decodeResource(mContext.getResources(),R.drawable.default_file_preview);
+    }
+
+
+}